Abstract
Abstract. We use an ensemble of aircraft, satellite, sonde, and surface observations for April–May 2006 (NASA/INTEX-B aircraft campaign) to better understand the mechanisms for transpacific ozone pollution and its implications for North American air quality. The observations are interpreted with a global 3-D chemical transport model (GEOS-Chem). OMI NO2 satellite observations constrain Asian anthropogenic NOx emissions and indicate a factor of 2 increase from 2000 to 2006 in China. Satellite observations of CO from AIRS and TES indicate two major events of Asian transpacific pollution during INTEX-B. Correlation between TES CO and ozone observations shows evidence for transpacific ozone pollution. The semi-permanent Pacific High and Aleutian Low cause splitting of transpacific pollution plumes over the Northeast Pacific. The northern branch circulates around the Aleutian Low and has little impact on North America. The southern branch circulates around the Pacific High and some of that air impacts western North America. Both aircraft measurements and model results show sustained ozone production driven by peroxyacetylnitrate (PAN) decomposition in the southern branch, roughly doubling the transpacific influence from ozone produced in the Asian boundary layer. Model simulation of ozone observations at Mt. Bachelor Observatory in Oregon (2.7 km altitude) indicates a mean Asian ozone pollution contribution of 9±3 ppbv to the mean observed concentration of 54 ppbv, reflecting mostly an enhancement in background ozone rather than episodic Asian plumes. Asian pollution enhanced surface ozone concentrations by 5–7 ppbv over western North America in spring 2006. The 2000–2006 rise in Asian anthropogenic emissions increased this influence by 1–2 ppbv.
Highlights
Rapid industrial development in eastern Asia and in China has resulted in unprecedented growth in NOx emissions with implications for both regional and global tropospheric ozone (Wild and Akimoto, 2001)
Better understanding the impact of rising Asian NOx emissions on transpacific ozone pollution and surface ozone air quality in the United States is of great interest. We address this issue here through a global 3-D model analysis of observations from the NASA Intercontinental Chemical Transport Experiment – Phase B (INTEX-B) aircraft campaign, conducted in spring 2006 over the Northeast Pacific
We find in the model that the 20002006 rise of Asian anthropogenic emissions increased surface ozone by 1–2 ppbv in the western United States
Summary
Rapid industrial development in eastern Asia and in China has resulted in unprecedented growth in NOx emissions with implications for both regional and global tropospheric ozone (Wild and Akimoto, 2001). Better understanding the impact of rising Asian NOx emissions on transpacific ozone pollution and surface ozone air quality in the United States is of great interest. We address this issue here through a global 3-D model analysis of observations from the NASA Intercontinental Chemical Transport Experiment – Phase B (INTEX-B) aircraft campaign, conducted in spring 2006 over the Northeast Pacific. Background ozone levels in air entering western North America have increased approximately 10 ppbv between 1984 and 2002 (Jaffe et al, 2003) and ozone concentrations across the western United States show a significant increase with a mean trend of 0.26 ppbv a−1 (Jaffe and Ray, 2007) The cause for this increase is not clear but rising Asian emissions may be a contributing source. Study (IONS) (Thompson et al, 2008) to test model results, and use ground-based measurements at Mount Bachelor Observatory in central Oregon (Jaffe et al, 2005; Reidmiller et al, 2008) to link observed Asian pollution influences in the free troposphere to North American surface air quality
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
